Struggling with XML? Can't figure out the difference between an entity and a namespace? Fear not - our XML series has all the answers. This introductory article discusses the origins and design goals of XML, the basic rules of XML markup, and how to use elements and attributes in an XML document.
They say that the whole is greater than the sum of its parts...and nowhere is this seen more clearly than with XML and its ancillary technologies. Over the past year and a half, the XML universe has grown by leaps and bounds to include many new technologies, most with hard-to-remember acronyms. Here's a quick list of the important ones, and how they fit into the larger picture:
XML Schema: XML Schema makes it possible to define the structure and format of "classes" of XML documents, providing more advanced features than those offered by the regular Document Type Definition (DTD). Find out more about it at http://www.w3.org/XML/Schema
XLink: XLink is a specification for linking XML data structures together, in much the same way as the hyperlinks available in HTML...although XLink allows for far more sophisticated types of links, including simultaneous links to more than one resource. Find out more about it at http://www.w3.org/XML/Linking
XPointer: XPointer is a specification for navigating the hierarchical tree structure of an XML document, and referencing elements, attributes and other data structures within the document. Find out more about it at http://www.w3.org/XML/Linking
XSL and XSLT: The Extensible Stylesheet Language (XSL) makes it possible to apply presentation rules to XML documents, and convert - or transform - them from one format to another. Find out more about it at http://www.w3.org/Style/XSL/
XHTML: The next version of HTML, XHTML combines the precision of XML markup with the easy-to-understand tags of HTML to create a more powerful and flexible language. Find out more about it at http://www.w3.org/MarkUp/
XForms: XForms offers a way to improve the current crop of HTML-based forms by separating the function of the form from its appearance, thereby making it possible to easily adapt a form for display on a variety of devices and systems. Find out more about it at http://www.w3.org/MarkUp/Forms/
XML Query: The XML Query effort is focused on creating a specification that makes it possible to query one or more XML document(s) and generate usable result data (in much the same way as SQL is used to retrieve database records.) Find out more about it at http://www.w3.org/XML/Query
XML Encryption: XML Encryption is a means of encrypting and decrypting XML documents, so as to secure it against unauthorized usage. Find out more about it at http://www.w3.org/Encryption/2001/
The list of XML-related technologies keeps increasing, and you should always refer to the W3C's Web site at http://www.w3.org/ for the latest information.
This article copyright Melonfire 2001. All rights reserved.